When assessing neuromuscular function, standard strength tests are typically based on long-lasting (~3-5 s) maximum contractions providing the maximum force and, occasionally, the maximum rate of force development. However, the same tests do not sufficiently capture neural stimulation phenomena that dominate rapid discrete or consecutive actions of antagonistic muscle groups, or postural corrections, while requiring maximum contractions that could be inappropriate for some populations. As a result, the standard tests have demonstrated inconsistent and, on average, low external validity when used to predict functional movement performance in both healthy and various patient populations. The main aim of this proposal is to evaluate two novel protocols for evaluating neuromuscular function based on the mechanical output of short-lasting isometric muscular contractions. The reliability (for monitoring interventions over days/weeks), validity (regarding their relevance for predicting functional performance) and generalizability (regarding the generalization across different muscle groups of the same individual) of new protocols will be evaluated. The results are expected to provide a basis for further development of the evaluated protocols into standard tests of neuromuscular function. Subsequent research would then be proposed to more thoroughly investigate sensitivity of the dependent variables, to detect differences among various populations (e.g., healthy individuals vs. neurological patients, unilaterally affected extremities, different age groups) and evaluate the effects of various interventions. PUBLIC HEALTH RELEVANCE: In the typical assessment of neuromuscular function standard strength tests are based on the ability to exert long lasting maximal contractions. The relevance of such tests, regarding many daily movement tasks is limited, and the sustained exertion of maximum forces is inappropriate for some populations. The goal of this project to evaluate two novel testing protocols based on short lasting submaximal and maximal contractions that could provide a valid assessment of neuromuscular abilities relevant for a variety of everyday tasks in various subject populations.